Magnetic levitation systems have been designed in general as systems that levitate through the use of attraction or repulsion between two objects. These magnetic levitation systems are dependent upon the spacing of the two objects such that if the spacing of the two objects changes, the forces produced by the magnets on each of the objects change. Furthermore, in systems that implement magnetic levitation via a track, for example on trains, requires that the track be substantially level. Thus, if the ground shifts over time because of weather or weight of the train and track, the track will have to be repaired.
Magnetic levitation can provide advantages compared to conventional wheels on tracks. Generally, magnetic levitation has low or zero mechanical friction and thus parts in levitation systems do not wear from contact. Magnetic levitation has a wide range of speeds over which it can operate, and in operation it generates relatively low noise levels.
Magnetic levitation can be applied to traditional large train system architecture as well as monorail or personal rapid transport (PRT) systems. Magnetic levitation can use active or passive magnetic interaction for levitation and centering functions, and can use inductive or synchronous magnetic interaction for propulsion. For example, a networked guideway transit system can use permanent magnet coupling to provide primary lift passively with motion, and can use electrodynamic repulsion to create centering forces at most operational speeds while integrating linear motor functions with electrodynamic centering functions. See, for example, Wamble, III et al. U.S. Pat. No. 7,562,628 issued Jul. 21, 2009, incorporated herein by reference, and Wamble, III et al. U.S. Pat. No. 8,171,858 issued May 8, 2012, incorporated herein by reference. A propulsion or drive unit can be either integrated with or separate from a levitation unit.
For example, a propulsion unit separate from the levitation unit is described in Wamble III, International Publication WO 2013/003387 A2 published 3 Jan. 3, 2013, incorporated herein by reference. A vehicle can be levitated by one or more of the levitation units (for example, 410 in FIGS. 2, 3, 4, 9, 10, 11A, 11B of WO 2013/003387 A2), and each levitation unit has one or more elongated magnetic poles. When the vehicle engages a track, each elongated magnetic pole is adjacent to a flat vertical surface of a stationary electrically conductive rail of the track, and the elongated magnetic pole is inclined at a variable angle. When the elongated magnetic pole moves along the rail, the magnetic field from the elongated magnetic pole induces eddy currents in the rail, and the eddy currents in the rail produce lift upon the elongated magnetic pole. Under some typical operating conditions, the lift is generally proportional to the angle of inclination and the velocity of the vehicle. (See paragraphs [0066] to of WO 2013/003387 A2.)
The various embodiments described above are provided by way of illustration only and should not be construed to limit the scope of the disclosure. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes can be made in the detail, especially in matters of shape, size and arrangement of the parts within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms used in the attached claims. It will therefore be appreciated that the embodiments described above can be modified within the scope of the appended claims. Claim language reciting “at least one of” a set indicates that one member of the set or multiple members of the set satisfy the claim.